Average size of human heart : 300 grams (10.58 ounces)Average size of human arm : It is the size of the fist.Average size in Inches of human heart : Typical heart of an adult [1]: 4.7 in (12cm) in length 3.1 in (8cm) to 3.5 in (9cm) in breadth 2.4 in (6cm) in thicknessAverage weight of human heart : The weight of the average human heart is 10-12 ounces for a male and 8-10 ounces for a female. The weight increases with age and is especially noticeable in males.Man heart weight = 300gFemale heart weight = 200g